Companies that extrusion coat a variety of polymers, including low density polyethylene (LDPE), onto paper and paperboard, continually have problems obtaining good “fiber tear” adhesion, which is the amount of adhesion required, to have an adhesion between the polymer to the paper greater than the adhesion of the paper fibers to themselves. When the polymer is pulled from a paper substrate, if fiber tear occurs, this adhesion is considered acceptable. If the polymer is pulled from the paper without fibers (without fiber tear), this is considered unacceptable adhesion. Improved adhesion is also desired in the extrusion lamination process, which is used to manufacture multilayer substrates. Ethylene-based polymers used for coatings and films are disclosed in the following references: International Publication Nos. WO 2011/071843, WO 1991/18944; U.S. Pat. Nos. 5,178,960, 3,860,538, 4,714,741, 6,558,809, 4,962,164, 3,676,401; GB 1448062; EP 0230143B1; Ward et al., Ethylene-Carbon Monoxide Extrudable Adhesive Copolymers for Polyvinylidene Chloride, June 1988 Tappi Journal, pp. 140-144; Scott et al., Degradable Polymers, Principles and Applications, Chapter 8: Ethylene-carbon monoxide copolymers, pp. 156-168, Chapman and Hall (1995).
It is a well known that, when running extrusion coating lines, at higher and higher line speeds, with conventional polymers, unacceptable fiber tear adhesion results. This adhesion is related to the oxidation of the molten polymer as it exits the extrusion die, and before it comes in contact with the paper (or the time in the air gap). At higher line speeds, the molten polymer curtain has less time to oxidize, which can reduce adhesion. There is a need for new ethylene-based polymers that can be used in high speed extrusion coating lines, and which have good adhesion to paper substrates, and which can be used at lower melt temperatures, and/or at higher line speeds of the paper substrate. These needs have been met by the following invention.